Boris Johnson lost another close adviser yesterday over racism allegations. Nick Hoare, interim director at the London Development Agency, was sacked last night after using the n-word in a meeting.

By way of mitigation, he said:

“My boss, Sarah Ebanja, she is a coloured person. She knows I’m not racist.”

It is not the first time the Mayor of London has lost a racist adviser. In June last year, his director of political strategy James McGrath – a man described subsequently by David Cameron as “a good person” – was forced to resign after telling a black journalist that black Londoners should “go if they don’t like it here”.

The latest scandal is the sixth instance of Mr Johnson losing a senior aide in his 18 months in charge. Here are the other four:

• In June, Deputy Mayor for External Relations Ian Clement was fired after it emerged he lied about expense claims, treating his mistress to £150 worth of meals on his City Hall credit card.

• In December 2008, David Ross resigned as the Mayor’s Olympic adviser after breaking stock exchange rules by using £157 million of Carphone Warehouse shares to prop up his struggling property empire.

• In August 2008, Tim Parker resigned as First Deputy Mayor on the eve of taking control of Transport for London. According to the GMB, he once turned up in his Porsche to sack a group of factory workers.

• In July 2008, Ray Lewis, Deputy Mayor for Young People, resigned over “sex and financial” allegations. Mr Lewis claimed he was a JP – despite never having been a magistrate.

Mr Johnson has himself faced allegations of racism in the past, full details of which can be found here.

Like this article? Sign up to Left Foot Forward's weekday email for the latest progressive news and comment - and support campaigning journalism by making a donation today.